Current sanitation codes require urinals and other drains to provide a seal to contain gases and odors that develop in the drain system. Typical seals include the well known P-traps or S-traps, in which a residual portion of the flushing water forms a seal that effectively locks in odors from downstream of the seal. The upward surface of the seal communicates freely with the environment, which often requires frequent flushing to eliminate residual urine and prevent any odors emanating from the seals. Because of the need for frequent flushing, large amounts of water are often consumed, which can be problematic especially in areas with limited or no access to water.
“Waterless” or “water-free” urinals are becoming necessities as a result of the growing concern to limit unnecessary water usage. With an increasing emphasis on water conservation, there is heightened interest in toilets and urinals designed to minimize the amount of water used.
Various forms of waterless urinals are known that utilize cartridges having oil or other low-density sealants to prevent odors from emanating from the drain pipe. Exemplary patents include U.S. Pat. No. 5,711,037 to Reichardt et al., U.S. Pat. No. 6,053,197 to Gorges, U.S. Pat. No. 6,644,339 to Gorges et al., U.S. Pat. No. 6,959,723 to Gorges, and U.S. Pat. No. 6,973,939 to Gorges et al. The oil-based sealants float on a body of trapped residual urine and thereby serve as an odor barrier, which allows entering urine to immediately permeate downwardly through the sealant and proceed to a drain, while preventing odors from emanating through the seal.
The low-density sealant in these cartridges remains open to the atmosphere, which can be problematic as the sealant is depleted, and odors begin to permeate through the seal. In addition, these cartridges typically require periodic replacement, which can add significantly to the waterless urinals' cost, especially in high traffic areas such as airports and stadiums. In addition, removal of the cartridges generally requires a special tool, gloves, and masks. Furthermore, the used cartridges are often hazardous and require properly disposal.
In addition to chemical sealants, it is known to utilize a duck bill valve that opens from the weight of the fluid. See, for example, U.S. Pat. No. 6,401,266 to Mitchell et al.; U.S. Pat. Appl. No. 2006/0010565 to Cummings (publ. May 2006); U.S. Pat. Appl. No. 2006/0207005 to Janssen (publ. September 2006); and WIPO Patent Appl. No. 2009/040524 to McAlpine (publ. April 2009). However, such valved systems typically retain a small amount of fluid in the valves after each use, which can cause odors to emanate from the valves. In addition, the valves are generally prone to freezing in cold regions, and sticking. In addition, the systems utilize only a single valve, which can be problematic if the valve is stuck open due to sticking or freezing, debris, or otherwise.
U.S. Pat. No. 6,286,153 to Keller discusses a urinal cartridge that includes an electrically operated float valve. The Keller system also utilizes only a single valve and therefore suffers from the disadvantages discussed above.
It is also known to use an umbrella valve in a urinal. See, for example, U.S. Pat. No. 4,180,875 to Wilson, which discusses a urine disposal bypass unit having a one-way valve. The Wilson system is problematic as the system also utilizes a single valve. In addition, the system lacks a removable core and therefore increases the time and cost for cleaning and maintenance of the valve and bypass unit.
Thus, there is still a need for a mechanism for a waterless urinal that operates in a closed system and without the need for a chemical sealant.